BUYERS GUIDE
Hexa is a supplier of fine Colombian emeralds, with involvement at each stage of the supply chain. We provide the very finest investment grade emeralds to high-end jewellers, wholesalers and collectors. The business has a truly international presence with our head office located in London and our manufacturing office in the heart of Bogota’s emerald district, ensuring the constant supply of extra fine quality emeralds for the international market at competitive prices.
We place great importance in working to stringent buying/manufacturing guidelines and export fine stones that meet the quality standards and expectations of our clients. Each Emerald is recorded and certified by up to two, sometimes three laboratories, CDTEC in Colombia and then in Switzerland by the SSEF or Gubelin to verify the provenance, quality and treatment of the stone.
The quality and value of an emerald is dependant on a combination of the following criteria:
CARAT
An emerald’s weight is measured in carats. 5 carats = 1 gram. The term carat is derived from the ‘carob seed’ that was used in India as a measure of weight for precious stones. All other criteria being equal, the greater the carat weight, the rarer the emerald and therefore greater its value. Illustrated below is the approximate appearance of a well cut octagon shaped emerald for a given carat weight. It is worth noting that emeralds are less dense than diamonds which means if you place two 1 carat stones side by side, the emerald will generally appear around 30% bigger.
Carat Size
0.25 0.50 0.75 1.00 1.50 2.002.50 3.00 5.00 10.00
COLOUR
Colour is a matter of personal preferance. Emeralds vary in colour depending mainly upon their chromium and vanadium content. Therefore emeralds from different countries and mines have different predominant colours. Emeralds range from bluish to yellowish shades. But, a natural colour will always have a greater value than an equivalent colour obtained by any other process, on ocassion emeralds can be filled with coloured oils to improve their colour. None of the emeralds sold by IEEX are treated in this fashion. CLARITY
INCLUSIONS The clarity of an emerald is determined by the number, size and location of inclusions which are present in the stone. They reflect its fascinating geological aspects. Internally and externally too, there may be the presence of fissures, fractures and cavities which affect clarity.
Eye Clean Slightly Included Included
Insignificant Minor Moderate Significant Very Significant
TRANSPARENCY Transparency refers to the ability of an emerald to transmit light. It is affected by the quantity or absence of opacity and brilliance present in the stone.
Transparent Translucent Opaque
SHAPE AND CUT
To optimize the natural rough, emeralds are cut into a variety of shapes such as those illustrated below. The cutting of emerald and other coloured stones is considered as much an art as it is a science. Unlike the perfectly symmetrical cuts prized by the diamond market, coloured stones are usually cut in a more artisanal fashion. The job of the cutter is to cut the stone in a fashion that releases the full potential of the rough material, capturing colour when necessary. The preferred cut is the ‘emerald cut’ which tends to command a premium over all others.
Oval Cushion Emerald Pear Heart
Square Round Marquise Baguette Cabochon
PROFILE
Cut refers to the accuracy of the angles, proportions, symmetry and polish of the emerald. It greatly affects how light travels within the emerald, and how it exits in the form of brilliance.
Proportional Deep Shallow Asymetric